"It was basically a coincidence," saysRafe Brown, an evolutionary biologist at the University of Kansas who was on the expedition team led by the Philippines-based Centre for Sustainability. "One of the students happened to be walking by it and thought it was a worm. But lo and behold, it was a Malatgan River caecilian."

Brown and his team have been wading across rivers and sifting through mud in the Palawan (map) backcountry for over 15 years looking for signs of this and other species lost to science.

WATCH: A researcher holds the Malatgan River caecilian (Ichythyophis weberi), an amphibian recently rediscovered in the Philippines after more than 50 years. Video courtesy Rafe Brown.

When the expedition finally stumbled across the serpentine amphibian, it was at the end of a road and a seven-hour hike beyond that from the nearest village. The area is known as Cleopatra's Needle.

Remarkably, the expedition also found the Palawan toadlet (Pelophryne albotaeniata), which had been missing for the last 40 years.

Lost and Found

The rediscoveries are the result of abiodiversity survey launched in December 2014 and carried out by the Palawan Council for Sustainable Development, Global Wildlife Conservation, the Amphibian Survival Alliance, and Rainforest Trust.

"When we started this project, we didn't know for sure if these animals were there," saysRobin Moore, conservation officer with the Amphibian Survival Alliance.

Joseph Mendelson, a herpetologist and director of research at Zoo Atlanta, adds that "discoveries like this reinforce the importance of continued biodiversity surveys around the world."

More Species Surprises?

While many of the Philippines' forests have fallen to development, mining, and agriculture, the island of Palawan is still relatively underdeveloped. A2013 study in Science deemed the Palawan Game Refuge and Bird Sanctuary as the fourth-most irreplaceable protected area in the world when it comes to protecting biodiversity and species found nowhere else.